Surgical laser treatment temperature monitoring

ABSTRACT

A surgical laser system includes a laser source configured to generate laser energy, a laser fiber optically coupled to the laser source and configured to discharge the laser energy and collect electromagnetic energy feedback from a treatment site, a photodetector configured to generate an output signal in response to the electromagnetic energy collected from the treatment site, a display, and a controller configured to produce an image or indication about the temperature at the treatment site on the display based on the output signal.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No.61/895,211, filed Oct. 24, 2013, and U.S. Provisional Application No.61/934,387, filed Jan. 31, 2014. The content of each of theabove-referenced applications is incorporated herein by reference in itsentirety for all purposes.

FIELD OF THE INVENTION

Embodiments of the present invention relate generally to the field ofmedical lasers utilizing optical fibers. More specifically, embodimentsof the present invention relate to the use of electromagnetic energyfeedback from a treatment site to provide a physician with real-timeinformation about conditions at the treatment site, such as, forexample, tissue temperature, laser treatment being performed, etc.

BACKGROUND

Embodiments of the present invention generally relate to surgical lasersystems and methods of operating or controlling such systems.

Surgical laser systems have been used in various practice areas, suchas, for example, urology, neurology, otorhinolaryngology, generalanesthetic ophthalmology, dentistry, gastroenterology, cardiology,gynecology, and thoracic and orthopedic procedures. Generally, theseprocedures require precisely controlled delivery of laser energy as partof the treatment protocol to cut, vaporize or ablate targeted tissue,such as cancerous cells and prostate tissue, for example.

Black body radiation is one of the basic phenomena in physics, which hasbeen commonly used for measuring the temperature of the body. Generally,the subject in thermodynamic equilibrium will radiate electromagneticwaves having a specific spectrum and intensity that depends only on thetemperature of the body.

U.S. Pat. No. 7,869,016, which is assigned to the same assignee as thepresent application and the contents of which are incorporated herein byreference in their entirety for ail purposes, discloses a technique forprotecting the laser fiber tip by monitoring the black body radiationfrom the fiber tip. The intensity of the black body radiation is used toindicate a temperature of the fiber tip, which is used to automaticallyshut off the discharge of the laser energy when the temperature reachesan unsafe condition. Thus, in this instance, a physician does not havethe ability to alter the laser procedure being formed or to change theoperating parameters of the laser device to avoid system shut down.

The temperature achieved by exposing tissue or a treatment site to laserenergy plays an important role in determining the type of lasertreatment being performed (e.g. coagulation, vaporization, etc.), aswell as the effectiveness of the laser treatment. For example, it maynot be possible to perform a vaporization treatment or the vaporizationtreatment may be inefficient, if the temperature is too low at thetreatment site. Additionally, the temperature sensed at the treatmentsite may also indicate that the laser fiber, from which the laser energyis discharged, may suffer damage due to overheating the fiber tip.

It would be desirable to provide real-time laser treatment sitetemperature information to assist the physician during a surgical lasertreatment to: identify the laser treatment being performed, improve theefficiency of the laser treatment by, for example, preventingovertreatment or under treatment, warn the surgeon of potential fibertip damage, and/or provide other benefits currently unavailable tophysicians.

SUMMARY

Embodiments of the present invention are directed to a surgical lasersystem including laser source configured to generate laser energy and alaser fiber optically coupled to the laser source and configured todischarge the laser energy and collect electromagnetic energy feedbackfrom a treatment site in a patient. The surgical laser system alsoincludes a photodetector configured to generate an output signal inresponse to the electromagnetic energy collected front the treatmentsite, a display and a controller configured to produce an image orindication about at least one condition at the treatment on the displaybased on the output signal.

Embodiments of the present invention are also directed to a method ofoperating a surgical laser system comprising the steps of generatinglaser energy using a laser source and discharging the laser energythrough a laser fiber to a treatment site. The method also includesdelivering electromagnetic energy feedback from the treatment siteproduced in response to discharging the laser energy to the treatmentsite to a photodetector and generating a photodetector output signalbased on the electromagnetic energy feedback. After the photodetectoroutput signal is generated, the photodetector output signal is analyzedusing a controller to determine the treatment site information (i.e.,conditions at the treatment site). Once analyzed by the controller, thistreatment site information is displayed on a display for a physician tosee.

In another embodiment of the present invention, a method of operating asurgical laser system is provided, the method comprises the steps ofgenerating laser energy using a laser source, discharging the laserenergy through a laser fiber to a treatment site, analyzingelectromagnetic energy feedback from the treatment site produced inresponse to discharging the laser energy to the treatment site, andautomatically adjusting the laser energy based on the analysis of theelectromagnetic energy feedback.

For a better understanding of the embodiments of the present invention,its operating advantages and specific objects attained by its uses,reference is made to the accompanying descriptive matter in whichpreferred embodiments of lire invention are illustrated in theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a simplified diagram of a surgical laser system in accordancewith embodiments of the present invention performing an exemplarysurgical laser treatment;

FIG. 2 is a simplified diagram of a distal end of a laser fiber of thesurgical laser system of FIG. 1 within an endoscope performing anexemplary laser treatment;

FIG. 3A is a graph depicting black body radiation as a laser fiber ismoved across targeted tissue at 1 nm/s;

FIG. 3B is a photograph of the vaporization effect on the targetedtissue as the laser fiber is moved across the targeted tissue at 1min/s;

FIG. 4A is a graph depicting black body radiation as a laser fiber ismoved across targeted tissue at 4 nm/s;

FIG. 4B is a photograph of the vaporization effect on the targetedtissue as the laser fiber is moved across the targeted tissue at 4 mm/s;

FIG. 5A is a graph depicting black body radiation as a laser fiber ismoved across targeted tissue at 16 nm/s;

FIG. 5B is a photograph of the vaporization effect on the targetedtissue as the laser fiber is moved across the targeted tissue at 16mm/s;

FIG. 6 is a graph in linear scale depicting the black body radiation asa function of laser fiber scanning speed;

FIG. 7 is the graph depicted in FIG. 6 in logarithmic scale;

FIG. 8 is a simplified diagram of a display in accordance withembodiments of the invention; and

FIG. 0 is a flowchart illustrating a method of operating a surgicallaser system in accordance with embodiments of the invention.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

Embodiments of the present invention generally relate to surgical lasersystems and methods of controlling surgical laser systems, such asduring performance of a laser treatment on a patient. Embodiments of theinvention are described more fully hereinafter with reference to theaccompanying drawings. The various embodiments of the invention may,however, be embodied in many different forms and should not be construedas limited to the embodiments set forth herein. Rather, theseembodiments are provided so that this disclosure will be thorough andcomplete, and will fully convey the scope of the invention to thoseskilled in the art. Elements that are identified using the same orsimilar reference characters refer to the same or similar elements.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of the invention. Asused herein, the singular forms “a”, “an” and “the” are intended toinclude the plural forms as well, unless the context clearly indicatesotherwise. It will be further understood that the terms “comprises”and/or “comprising,” when used in this specification, specify thepresence of stated features, integers, steps, operations, elements,and/or components, but do not preclude the presence or addition of oneor more other features, integers, steps, operations, elements,components, and/or groups thereof.

It will be understood that when an element is referred to as being“connected” or “coupled” to another element, it can be directlyconnected or coupled to the other element or intervening elements may bepresent. In contrast, if an element is referred to as being “directlyconnected” or “directly coupled” to another element, there are nointervening elements present.

It will be understood that, although the terms first, second, etc. maybe used herein to describe various elements, these elements should notbe limited by these terms. These terms are only used to distinguish oneelement from another. Thus, a first element could be termed a secondelement without departing from the teachings of the present invention.

Unless otherwise defined, ail terms (including technical and scientificterms) used herein have the same meaning as commonly understood by oneof ordinary skill in the art to which this invention belongs. It will befurther understood that terms, such as those defined in commonly useddictionaries, should be interpreted as having a meaning that isconsistent with their meaning in the context of the relevant art andwill not be interpreted in an idealized or overly formal sense unlessexpressly so defined herein.

As will further be appreciated by one of skill in the art, the presentinvention may be embodied as methods, systems, and/or computer programproducts. Accordingly, the present invention may take the form of anentirely hardware embodiment, an entirely software embodiment or anembodiment combining software and hardware aspects. Furthermore, thepresent invention may take the form of a computer program product on acomputer-usable storage medium having computer-usable program codeembodied in the medium. Any suitable computer readable medium may beutilized including haul disks, CD-ROMs, optical storage devices, ormagnetic storage devices.

The computer-usable or computer-readable medium referred to herein as“memory” may be, for example hut not limited to, an electronic,magnetic, optical, electromagnetic, infrared, or semiconductor system,apparatus, device, or propagation medium. More specific examples (anon-exhaustive list) of the computer-readable medium would include thefollowing: an electrical connection having one or more wires, a portablecomputer diskette, a random access memory (RAM), a read-only memory(ROM), an erasable programmable read-only memory (EPROM or Flashmemory), an optical fiber, and a portable compact disc read-only memory(CD-ROM). Note that the computer-usable or computer-readable mediumcould even bee paper or another suitable medium upon which the programis printed, as the program can be electronically captured, via, forinstance, optical scanning of the paper or other medium, then compiled,interpreted, or otherwise processed in a suitable manner, if necessary,and then stored in a computer memory.

Embodiments of the present invention are also described using flowchartillustrations and block diagrams, it will be understood that each block(of the flowcharts and block diagrams), and combinations of blocks, canbe implemented by computer program instructions. These programinstructions may be provided to one or more controllers each comprisingone or more processor circuits, such as a microprocessor,microcontroller or other processor, such that the instructions whichexecute on the processors) create means for implementing the functionsspecified in the block or blocks. The computer program instructions maybe executed by the processors) to cause a series of operational steps,to be performed by the processors) to produce a computer implementedprocess such that the instructions which execute on the processors)provide steps for implementing the functions specified in the block orblocks.

Accordingly, the blocks support combinations of means for performing thespecified functions, combinations of steps for performing the specifiedfunctions and program instruction means for performing the specifiedfunctions. It will also be understood that each block, and combinationsof blocks, can be implemented by special purpose hardware-based systemswhich perform the specified functions or steps, or combinations ofspecial purpose hardware and computer instructions.

Embodiments of the present invention are directed to a surgical lasersystem anti methods of operating or controlling the system to perform,for example, a surgical laser treatment on a patient, such as,coagulation, tissue vaporization, tissue ablation, tissue cutting,kidney or bladder stone fragmentation (i.e., laser lithotripsy), orother surgical laser treatments. In some embodiments, the systemutilizes laser energy feedback or radiation feedback from the treatmentsite that is produced in response to exposure of the treatment site tolaser energy generated by the system to determine an approximatetemperature of the treatment site. In some embodiments, the approximatetemperature is displayed for the physician in real-time, and/or used todetermine an operating mode of the system that is indicative of thelaser treatment being performed at the treatment site.

FIG. 1 is a simplified diagram of a surgical laser system KM) formed inaccordance with embodiments of the present invention. In someembodiments, the system 100 includes a laser source 102, a waveguide orlaser fiber 104, a photodetector 106, a display 107, and a controller108. The laser source 102 is configured to generate laser energy,generally referred to as 110. The laser fiber 104 is optically coupledto the laser source 102 using, for example, a lens or other conventionaltechnique. The laser fiber 104 is configured to discharge the laserenergy 110 generated by the laser source 102 to a targeted treatmentsite 120. The photodetector 106 is configured to generate an outputsignal 112 representative of electromagnetic energy feedback 114produced at the treatment site 120 in response to the discharge of thelaser energy 110 front the laser fiber 104. In some embodiments, thecontroller 108 is configured to produce an image 140 on a display 107based on the output signal 112.

The laser source 102 may comprise one or more laser generators, whichare used to produce the laser energy 110. Each laser generator maycomprise conventional components, such as a laser resonator, to producethe laser energy 110 having the desired power and wavelength. In someembodiments, the laser energy 110 has a wavelength of approximately 532nm (green laser energy). Other wavelengths of the laser energy 110 mayalso be used, such as laser energy having a wavelength of approximately400-475 nm (blue laser energy), or laser energy having a wavelength ofapproximately 2000-2200 nm, which is suitable for performing laserlithotripsy procedures, for example. Those and other wavelengths may beused for the laser energy 110 depending on the laser treatment to beperformed.

In some embodiments, the laser energy 110 generated by the laser source102 is optically coupled to the laser fiber 104 through a conventionaloptical coupler (not shown), which may include lenses. The laser fiber104 may include arty conventional surgical laser waveguide, such as anoptical fiber. In some embodiments, the laser fiber 104 is configured todischarge the laser energy 110 at a distal end 116. The distal end orfiber tip 116 of the laser fiber 104 may be configured to discharge thelaser energy 110 laterally (i.e., side-firing fiber), as shown in FIG.1, along the axis 117 of the laser fiber 104 (i.e., end-firing fiber),as shown in MCI. 2, or in another conventional manner.

During a surgical laser treatment, the laser energy 110 is dischargedfrom the distal end 116 of the laser fiber 104 toward targeted tissue orobject 120 at the laser treatment site 121 to perform the desired lasertreatment on the targeted object 120. As used herein, the term “targetedobject” means an object of a patient on which a laser treatment isintended to be performed, such as a tumor, prostate tissue or other bodytissue, or a kidney or bladder stone, for example. Embodiments of theinvention utilize the black body radiation or electromagnetic energyfeedback 114 produced at the treatment site 121 in response to thedischarge of the laser energy 110 from the fiber tip 116, as anindication of the temperature at the treatment site 121 or the targetedobject 120 at the treatment site, and/or as an indicator of the laserenergy treatment being performed on the object 120 at the treatment site121.

In experiments performed ex vivo on porcine kidneys, laser energy 110was delivered to targeted tissue 120 on the porcine kidneys by a fiber104. The black body radiation or electromagnetic energy feedback 114produced at the treatment site 121 in response to the discharge of thislaser energy 110 from the fiber tip 116 was then collected by the laserfiber 104 and analyzed. Three experiments were performed where the laserfiber 104 was moved across the targeted tissue 120 at different speedsand the resulting black body radiation or electromagnetic energyfeedback 114 produced was collected and plotted on a graph.

FIG. 3A is a graph that depicts the black body radiation along theY-axis and the corresponding time in seconds along the X-axis as thelaser fiber 104 was moved across the targeted tissue 120 at 1 mm/s. From0 seconds to approximately 4 seconds, the laser source 102 was off. Fromapproximately 4 seconds to approximately 17 seconds, the laser source102 was turned on anti the laser fiber 104 was moving across an aluminumtray that was supporting the porcine kidney. From approximately 17seconds to approximately 28 seconds, the laser source 102 was on and thelaser fiber 104 was moving across the targeted tissue 120. Fromapproximately 28 seconds to approximately 34 seconds, the laser source102 was on and the laser fiber 104 was moving across the aluminum traythat was supporting the porcine kidney, lastly, at approximately 34seconds, the laser source 102 was turned off. As can clearly be seenfrom the graph, the black body radiation increased front approximately7500 to approximately 15000 when the laser fiber 104 was moving acrosslive targeted tissue 120 between 17 seconds and 28 seconds. FIG. 3B is aphoto that shows the vaporization groove created in the porcine kidneytissue 120 when the laser fiber 104 was moved across the targeted tissue120 at a rate of 1 mm/s.

FIG. 4A is a graph that depicts the black body radiation along theY-axis anil the corresponding time in seconds along the X-axis as thelaser fiber 104 was moved across the targeted tissue 120 at 4 nm/s. From0 seconds to approximately 1 second, the laser source 102 was off. Fromapproximately 1 second to approximately 7 seconds, the laser source 102was turned on and the laser fiber 104 was moving across the aluminumtray that was supporting the porcine kidney. From approximately 7seconds to approximately 13 seconds, the laser source 102 was on and thelaser fiber 104 was moving across the targeted tissue 120. Atapproximately 13 seconds, the laser source 102 was turned off. As canclearly be seen from the graph, the black body radiation increased fromapproximately 7500 to approximately 10000 when the laser fiber 104 wasmoving across the targeted tissue 120 between 7 seconds and 13 seconds.FIG. 4B is a photo that shows the vaporization groove created in theporcine kidney tissue 120 when the laser fiber 104 was moved across thetargeted tissue 120 at a rate of 4 mm/s.

FIG. 5A is a graph that depicts the black body radiation along theY-axis and the corresponding time in seconds along the X-axis as thelaser fiber 104 was moved across the targeted tissue 120 at 16 nm/s.Prom 0 seconds to approximately 0.5 seconds, the laser source 102 wasoff. Prom approximately 0.5 seconds to approximately 1.5 seconds, thelaser source 102 was turned on and the laser fiber 104 was moving acrossthe aluminum tray that was supporting the porcine kidney, fromapproximately 1.5 seconds to approximately 7.5 seconds, the laser source102 was on and the laser fiber 104 was moving across the targetedporcine tissue 120. At approximately 7.5 seconds, the laser source 102was turned off. As can clearly be seen from the graph, the black bodyradiation increased from approximately 8000 to approximately 8500 whenthe laser fiber 104 was moving across the targeted tissue 120 between1.5 seconds and 7.5 seconds. FIG. 5B is a photo that shows thevaporization groove created in the porcine kidney tissue 120 when thelaser fiber 104 was moved across the targeted tissue 120 at a rate of 16mm/s.

As depicted in FIGS. 3A, 4A and 5A, one can clearly identify an increasein the black body radiation or electromagnetic energy feedback 114produced when the laser source 102 was on and the laser fiber 104 movedacross the targeted tissue 120. Also, as depicted in FIGS. 3B, 4B and5B, by moving the laser fiber 104 across the targeted tissue 120 atdifferent speeds, one can create different degrees of vaporization suchthat vaporization increases when the laser fiber 104 is moved across thetargeted tissue 120 at slower speeds (FIG. 3B) and vaporizationdecreases when the laser fiber 104 is moved across the targeted tissue120 at slower speeds (FIG. 5B). Because the degree of vaporizationcorrelates to the temperature of the targeted tissue being vaporized,one can also correlate the temperature of the targeted tissue 120 beingvaporized to the black body radiation or electromagnetic energy feedback114 produced.

Depicted in FIGS. 6 and 7 are graphs showing the correlation of theintensity of the black body radiation 114 and hence, the vaporizationdegree to the laser fiber KM scanning or moving speed across thetargeted tissue 120. As can clearly be seen in FIG. 6 where the valuesalong the X and Y axes are in linear scale, the black body radiationintensity 114 (Y axis) increases with the degree of vaporization, whichcorresponds to an increase in the targeted tissue 120 temperature. Ascan clearly be seen in FIG. 7, with the values along the X and Y axesnow in logarithmic scale, there is a high correlation betweenvaporization degree and blackbody radiation intensity 114, where thecorrelation coefficient r² is close to 1. Therefore, we believe that onecan use the black body radiation or electromagnetic energy feedback 114produced on the targeted tissue 120 as an indicator of tissuevaporization degree. Accordingly, based on the electromagnetic energyfeedback 114 produced on the targeted tissue 120, the current operatingmode or laser treatment being performed at the treatment site (i.e.,coagulation, low vaporization, high vaporization, carbonization, etc.)can be identified in real-time and communicated back to the physicianinstantaneously.

In some embodiments, the electromagnetic energy feedback 114 (or blackbody radiation) collected from the fiber tip 116 is delivered to thephotodetector 106 through either the laser fiber 104 or through anothercomponent. Because the electromagnetic energy feedback 114 is light inthe infrared (IR) or far infrared (FIR) range that is emitted at thetreatment site 121 as temperature increases as a result of the lasertreatment, this IR or FIR light is collected by the laser fiber 104 andtransmitted back to the photodetector 106 as a result of the laser fiber104 having the ability to transmit light in two directions. Once theelectromagnetic runic energy feedback 114 is received and analyzed bythe photodetector 106, the photodetector 106 produces an output signal112 that is indicative of an approximate temperature at the treatmentsite 121, such as the temperature of the targeted object 120.

In some embodiments, live system 100 includes a dichroic beam splitteror a mirror 128 that reflects the electromagnetic energy feedback 114while allowing the laser energy 110 to pass through, as shown in FIG. 1.The electromagnetic energy feedback 114 reflected by the mirror 128 isdelivered to the photodetector 106. It is understood that the componentsof the system 100 could be modified such that the mirror 128 reflectsthe laser energy 110 from the laser source 102 to the optical coupler,while allowing the electromagnetic energy feedback 114 to puss throughthe mirror 128.

In some embodiments, the mirror 128 is highly transmissive over thewavelengths of the laser energy 110 and highly reflective over thewavelengths of the electromagnetic energy feedback 114. Thus,electromagnetic energy feedback 114, which is the black body radiationof targeted objects 120 at the treatment site 121 having a wavelengththat is different from the wavelength of the laser energy 110, may bereflected by the mirror 128 to the photodetector 106 while the laserenergy 110 discharged from the laser source 102 passes through themirror to the laser fiber 104.

In some embodiments, the mirror 128 includes a central hole (not shown),through which the laser energy 110 generated by the laser source 102 isdischarged. Portions of the electromagnetic energy feedback 114 impactthe mirror 128 outside the edges of the hole, and are reflected by themirror 128 to the photodetector 106. This embodiment of the mirror isparticularly necessary when the electromagnetic energy feedback 114comprises the reflected laser energy 110.

In some embodiments, the system 100 includes one or more filters 130that are configured to filter frequencies of the electromagnetic energyfeedback 114, and deliver filtered electromagnetic energy feedback 114to the photodetector 106. Exemplary embodiments of the one or morefilters 130 include a low-pass filter, a high-pass filter, and/or aband-pass filter. For example, a band-pass filter between 1.4 um to 1.8um can be used to monitor the electromagnetic feedback 114, althougheven longer wavelength band-pass filters can also be useful. Thus,embodiments of the output signal 112 include an output signal 112generated by the photodetector 106 in response to the electromagneticenergy feedback 114 or the filtered electromagnetic energy feedback 114.In order to simplify the discussion, references to the output signal 112include the output signal 112 generated in response to the filtered oran filtered electromagnetic energy 114, unless described otherwise orinapplicable.

In some embodiments, the one or more filters 130 and photodetector 106may be replaced with a spectrometer that analyzes the electromagneticenergy feedback 114 and outputs information, such as intensity levels ofthe electromagnetic energy feedback 114 over a range of wavelengths orfrequencies, and/or other information. In some embodiments, thespectrometer outputs only intensity levels of the electromagnetic energyfeedback 114 at certain frequencies of interest. In order to simplifythe discussion, references to the output signal 112 should also beinterpreted as describing embodiments in which the output signal 112 isreplaced with spectrometer information generated by a spectrometer inresponse to an analysis of electromagnetic energy feedback 114.

In some embodiments, the controller 108 represents conventionalelectronics and processors that may execute program instructions storedin memory 132 of the system 100, or other locations, to perform variousfunctions described herein. In some embodiments, (be controller 108processes (e.g., amplifies) and/or analyzes the output signal 112 todetermine an approximate temperature indicated by the signal 112 of thetreatment site 121 and/or the targeted objects 120. In some embodiments,the system 100 is calibrated to ensure that the approximate temperatureindicated by the output signal 112 is an accurate approximation of theactual temperature at the treatment site 121.

In some embodiments, the output signal 112 can be analyzed and displayedto determine the Joule usage corresponding to different vaporizationlevels or different laser treatments being performed.

In some embodiments, electromagnetic energy feedback 114 can bemodulated using an optical chopper or any other intensity modulator orinherent modulation (such as Q-switch pulsed laser) to generate amodulated output signal 112 from the photodetector 106. The controller108 can then demodulate this signal through a demodulator, such asphase-locked loop or multiplier using software or additional hardwareincluded with the controller, to extract the electromagnetic energyfeedback 114. In this way, the signal-to-noise ratio can be improved byeliminating any environmental or background electromagnetic energy, suchas the energy of radiation from the laser cavity, and any dark noisefrom the photodetector 106.

As described above, the controller 108 is configured to produce an image140 on the display 107 based on the output signal 112. In someembodiments, as depicted in FI. 8, the image 140 includes temperatureinformation and/or operating mode information 144, both of which aredetermined based on the approximate temperature indicated by the outputsignal 112. The temperature information indicates the approximatetemperature at the treatment site 121. In some embodiments, thetemperature information indicates an average approximate temperature atthe treatment site, which is calculated using the controller 108 basedon samples of the output signal 112 taken over a period of time, such as0.1-1.0 seconds. In some embodiments, the operating mode information 144indicates a laser treatment being performed at the treatment site 121 oron a targeted object 120 using the laser energy 110.

In some embodiments, the image 140 includes information regarding theJoule usage including the Joules currently being used at the treatmentsite 121 allows the physician to determine the efficiency of the lasertreatment being performed. For example, if the physician knows that 100KJ has been used and he/she knows there is high vaporization at thetreatment site, he/she knows that vaporization is being performedefficiently. However, if 100 KJ has been used and he/she knows there islow vaporization occurring at the treatment site, this may be anindication of low vaporization efficiency, which could lead tooverheating of the laser fiber 104 or the targeted tissue 120. Thisadditional information will allow a physician to identify and controlthe efficiency of the laser treatment being performed at the treatmentsite as well as help prevent the laser fiber 104 from overheating.

The image 140 produced on the display 107 using the controller 108changes in response to changes to the output signal 112. That is, as theoutput signal 112 indicates a change in the temperature information(i.e., approximate temperature at the treatment site 121) or theoperating mode information, the image produced on the display 107 by thecontroller 108 changes. Preferably, these changes to the image 140 areproduced in substantially real-time. As a result, as the output signal112 indicates a change, in the approximate temperature at the treatmentsite 121, the image 140 produced on the display 107 changes to indicatethis change in the approximate temperature. Likewise, changes in theoutput signal 112 that indicate a change in the operating mode result ina change m the operating mode information 144 produced in the image 140.Based on these changes in temperature and/or operating mode, thephysician can compensate in real-time as deemed necessary in order tocontinue with the laser procedure. For example, the physician can alterthe way the procedure is being performed/i.e., the distance of the fibertip from the targeted object 120 can be changed, etc.) or can change theoperating inputs of the laser device, i.e., the physician can increaseor decrease the power of the laser device, or the physician can changethe laser pulse widths, repetition rate, modulation, wavelength, etc.

In some embodiments, the image 140 includes a graphical display of thetemperature information, as shown in FIG. 8. For instance, thetemperature information may be presented in the image 140 in the form ofa bar graph 142. Lower approximate temperatures at the treatment site121 are indicated by a shorter bar, and higher approximate temperaturesat the treatment site 121 are indicated by a higher bar. In someexemplary embodiments, the graphical display indicating the temperatureinformation may include a line chart that presents the approximatetemperature at the treatment site or target object over time.

In some embodiments, the temperature information is presentedalphanumerically in the image 140 on the display 107. For instance, thetemperature information in the image 140 may include the approximatetemperature (e.g. 100° C.) indicated by the current output signal 112.

In some embodiments, the temperature information in the image 140 isrepresented both graphically and alphanumerically, as shown in FIG. 8.Additionally, the bar graph 142 may include the current approximatetemperature listed adjacent the bar graph, as well as a temperaturescale for the bar graph.

In some embodiments, the system 100 is configured to operate in at leasttwo different operating modes, each corresponding to a different lasertreatment (i.e., vaporization and coagulation) or any others describedabove. In some embodiments, the system 100 determines the mode ofoperation and the laser treatment being performed by the laser energy110 based on the output signal 112 using the controller 108.

In some embodiments, the laser treatments and operating modes that areidentifiable by the system 100 each have a corresponding approximatetemperature range that is bounded by upper and lower approximatetemperatures. In some embodiments, the approximate temperature ranges ofeach of the modes of operation of the system 100 do not overlap. In someembodiments the memory 132 of the system 100, or other memory, includesa mapping of the approximated temperature indicated by the output signal112 and the corresponding operating mode or laser treatment, which isaccessible by the controller 108.

During operation, the controller 108 determines the laser treatmentbeing performed at the laser treatment site 121 by comparing theapproximate temperature indicated by the output signal 112 to theapproximate temperature ranges associated with each of the lasertreatments or operating modes of the system 100, which, as mentionedabove, may be stored in the memory 132. When the approximate temperatureindicated by the output signal 112 falls within one of the approximatetemperature ranges of the laser treatments being monitored by the system100, that laser treatment is determined to be the laser treatment,currently being per burned at the laser treatment site 121. Operatingmode information indicating the currant operating mode or lasertreatment can then be presented in real-time in the image 140 on thedisplay 107 using the controller 108 allowing the physician to see theconditions at the treatment site 121 as they are occurring. For example,in FIG. 8, the operating module 144 is vaporization. In some exemplaryembodiments, the image indicating the operating mode or laser treatmentbeing performed may include a line chart or other indicator thatpresents the period of time an operating mode or laser treatment (i.e.,vaporization, coagulation, etc.) has been performed at the treatmentsite or the target object.

In one exemplary embodiment, the controller 108 is configured todetermine whether the system 100 is in a coagulation mode, in which thelaser treatment being performed at the laser treatment site is acoagulation treatment, based on the output signal 112. The coagulationtreatment causes blood exposed to the laser energy 110 at the lasertreatment site to coagulate. In another exemplary embodiment, thecontroller 108 is configured to determine whether the system 100 is in avaporization mode, in which the laser treatment being performed at thelaser treatment site is a vaporization treatment, based on the outputsignal 112. The vaporization treatment vaporizes tissue, blood, or othertargeted object 120 in response to exposure to the laser energy 110 atthe laser treatment site. Other embodiments involve the identificationof other operating modes of the system 100 and laser treatments by thecontroller 108 using the output signal 112. In a further exemplaryembodiment, the controller 108 is configured to determine whether thesystem is in coagulation mode or vaporization mode as indicated by theoperating mode 144 in FIG. 8.

In some embodiments, the coagulation mode of operation has anapproximate temperature range of between approximately 40-70° C. (n someembodiments, the vaporization mode of the system 100, in which avaporization laser treatment is performed at the laser treatment site,has an approximate temperature range of between approximately 80-150° C.

In some embodiments, the controller 108 is con fig oral to convert theoutput signal 112 from a lime-based signal to a frequency-based signal.This may allow the system 100 to extract more information from theelectromagnetic energy feedback 114. Hie signal conversion can beaccomplished through a frequency analysis of the output signal 112 usinga frequency analyzer, or through the application of a Fourier transformto the output signal 112.

In some embodiments, the frequency-bused output signal 112 can be usedto identify the laser treatment being performed at the laser treatmentsite 121. For instance, the controller 108 can determine whether thesystem 100 is operating in a coagulation mode or a vaporization modebased on the frequency-based output signal 112. In some embodiments, acoagulation treatment is indicated when the frequency-bused outputsignal 112 comprises lower frequency components that are relativelystable because during coagulation, no hubbies or debris are beingcreated at the treatment site 121. During a vaporization treatment,tissue debris and bobbles may form at tire treatment site, which willdisturb the laser energy feedback 114 collected from the fiber lip 116.This disturbance is manifested in the frequency-based output signalbeing less stable and having higher frequency components than that foundin the frequency-based signal corresponding to a coagulation treatment.Thus, in some embodiments, the controller 108 can distinguish differentmodes of operation based on an analysis of the frequency-based outputsignal produced in response to the electromagnetic energy feedback 114.

In some embodiments, the operating mode information in the image 140comprises alphanumeric and/or graphical information indicating thecurrent operating mode of the system 100. In some embodiments, thealphanumeric information includes a listing of the current operatingmode or laser treatment (e.g., vaporization), as indicated at 144 of theimage 140.

In some embodiments, the graphical information in the image 140indicating the current operating mode or laser treatment includes alower approximate temperature boundary 146 and an upper approximatetemperature boundary 148 for each operating mode, as shown in FIG. 8. Insome embodiments, the temperature information, such as the bar graph142, indicates the approximated temperature relative to the boundaries146 and 148, as shown in FIG. 8.

In some embodiments, the operating mode information in the image 140comprises a graphical display having a color that corresponds to thecurrent operating mode. For instance, when the approximate temperaturecorresponding to the output signal 112 indicates that the lasertreatment being performed at the laser treatment site 121 is acoagulation treatment, the operating mode information in the image 140includes a graphical image having a color that corresponds to thecoagulation mode. Likewise, when the output signal 112 indicates that avaporization treatment is being performed at the treatment site 121, thecontroller 108 produces tire image 140 having a graphical image of acolor that corresponds to the vaporization mode of operation. As aresult, the physician can quickly determine the laser treatmentcurrently being performed based on a color being displayed in the image140 on the display 107. This color may be presented, for example, ashighlighting of the bar graph 142, the listing of the operating mode,the display of the approximated temperature, a background of the image140, or in another suitable manner.

In some embodiments, each of the approximate temperature ranges of thelaser treatment modes performed by the system 100 have a targetapproximate temperature range corresponding to the preferred approximatetemperature for performing the laser treatment. For instance,coagulation laser treatments may be most efficient at a targetapproximate temperature range of between approximately 50-60° C., andvaporization laser treatments may be performed most efficiently within atarget approximate temperature range of between approximately 100-120°C.

In some embodiments, the operating mode information produced in theimage 140 indicates the target approximate temperature range for atleast one of the operating modes. In some embodiments, the targetapproximate temperature range for a mode or laser treatment is presentedgraphically in the image 140 by a lower approximate temperature boundary146′ and an upper approximate temperature boundary 148′ of the targetedapproximate temperature range, as shown in FIG. 8.

In some embodiments, the operating mode information for each operatingmode (i.e., coagulation or vaporization) includes at least two colorsthat may be produced in the image 140 to indicate the mode of operation.One of the colors for each mode of operation indicates that theapproximate temperature indicated by the output signal 112 is within theapproximate temperature range of the mode of operation, but is notwithin the target approximate temperature range for the mode ofoperation (i.e., outside of boundary lines 146′ and 148′ but withinboundary lines 146 and 148). The second color is used to indicate thatthe approximate temperature indicated by the output signal 112 is withinthe target approximate temperature range for the mode of operation(i.e., between boundaries 146′ and 148′). As mentioned above, the colormay be presented, for example, as highlighting of the bar graph 142, thelisting of the operating mode, the display of the approximatedtemperature, a background of the image 140, or in another suitablemanner.

In some embodiments, the operating mode information in the image 140changes based on the approximate temperature indicated by the outputsignal 112 anti the proximity of the approximate temperature to one ofthe approximate temperature boundaries 146 or 148 of an operating mode.In operation, as the approximate temperature rises toward a lowerapproximate temperature boundary 146 of an operating mode, the operatingmode information produced in the image 140 may indicate(alphanumerically and/or graphically in any manner previously disclosed)that the approximate temperature at the laser treatment site is not highenough to perform the laser treatment corresponding to the operatingmode. As the approximate temperature rises to the lower approximatetemperature boundary of the operating mode, the operating modeinformation produced in the image 140 indicates (alphanumerically and/orgraphically in any manner previously disclosed) that the laser treatmentis being performed. As the approximate temperature rises further intothe target approximate temperature range for the operating mode, theoperating mode information in the image 140 may indicate(alphanumerically and/or graphically in any manner previously disclosed)that the approximate temperature is within the target approximatetemperature range for the operating mode. As the temperature rises andexceeds the upper boundary 148′ of the target approximate temperaturerange, the operating mode information produced in the image 140 mayindicate (alphanumerically and/or graphically in any manner previouslydisclosed) that the laser treatment associated with the operating modeis still being performed at the laser treatment site, but that theapproximate temperature is no longer within the target approximatetemperature range. When the approximate temperature exceeds the upperapproximate temperature boundary 148 for the operating mode, theoperating mode information produced in the image 140 indicates(alphanumerically and/or graphically in any manner previously disclosed)that the laser treatment is no longer being performed.

In some embodiments, the controller 108 determines the type of fiber 104being used for a specific laser treatment being performed at the lasertreatment site 121 by comparing laser fiber 104 information stored inthe memory 132 with information from the current fiber 104 being used,the memory 132 can also include the operating parameters for each laserfiber 104 capable of being used with the system 100. Accordingly, thecontroller 108 can be configured to compare the stored, safe operatingparameters for the laser fiber 104 being used with operating informationfor the laser fiber 104 during use in performing a laser treatment. Ifthe operating information for the laser fiber 104 during use (i.e.,fiber lip temperature) falls outside the acceptable operatingparameters, the controller 108 can automatically shut down the system ortake other action, such as reducing laser power, in order to preventdamage to the laser fiber 104.

In some embodiments, the laser fiber 104 may be supported within anendoscope 150, a distal end of which is illustrated in FIG. 2. In someembodiments the system 100 includes a viewing fiber 152, a distal end ofwhich is illustrated in FIG. 2. The viewing fiber 152 may be used, forexample, to capture images of the treatment site 121, or perform otherfunctions.

In some embodiments, the controller 108 is configured to produce animage 154 received through the viewing fiber 152 on the display 107, asindicated in FIG. 8. In some embodiments, the image 154 from the viewingfiber and an image 140 produced by the controller 108 bawd on the outputsignal 112, may be simultaneously displayed on the display 107, as shownin FIG. 8. As mentioned above, the image 140, based on the output signal112 may include temperature information and/or operating modeinformation.

In some embodiments, the system 100 includes an output device 160, asshown in FIG. 1. In some embodiments, the controller 108 is configuredto output an audible signal using the output device (e.g. speaker) basedon the output signal 112. In some embodiments, the audible signalincludes temperature information indicative of an approximatetemperature at the treatment site, and/or operating mode informationindicating a laser treatment being performed at the treatment site. Forinstance, the audible signal may verbally indicate the approximatetemperature and/or the operating mode. In some embodiments, the audiblesignal includes a tone that's indicative of the approximate temperatureand/or operating mode. For instance, the audible signal may have apitch, amplitude, or pattern indicating the temperature information oroperating mode information. In some embodiments, the pitch, amplitude,or pattern of the audible signal changes in response to changes in theapproximate temperature indicated by the output signal 112. In someembodiments, the audible signal may include a verbal indication, apitch, amplitude, or pattern indicating which operating mode or lasertreatment is being performed and/or whether such laser treatment iswithin any of the target approximate temperature ranges.

In some embodiments, the system includes an input device 162 that thephysician may use to control the laser energy 110 discharged front thelaser source 102. In some embodiments, the input device comprises adial, a keypad, a touchscreen, or other suitable input device thatallows the physician to adjust the power level of the laser energy 110generated by the laser source 102. This adjustment to the power of thelaser energy may involve controlling a power supply 164, controlling ashutter mechanism 165, modulating the laser energy 110, adjusting a dutycycle of the laser energy 110, adjusting the power of the input light tothe laser gain medium of the laser resonator within the laser source102, or other conventional adjustment that modifies the power of thelaser energy 110 output from the laser source 102. In some embodiments,the input device 102 also allows the physician to adjust the laser pulsewidths, repetition rate, modulation and/or wavelength.

In some embodiments, the system 100 operates to maintain a desiredapproximate temperature or operating mode that the physician would likethe system 100 to operate at. In some embodiments, the physician inputsthe desired temperature or operating mode through the input device 162.In some embodiments, the controller 108 controls the laser source 102 toautomatically adjust the laser energy 110 output from the laser source102 based on the output signal 112 to maintain the approximatetemperature at the laser treatment site 121 at or near the desiredtemperature set by the physician, to maintain the approximatetemperature at the laser treatment site 121 within the range ofapproximate temperatures associated with the desired operating nudeselected by the physician, or to maintain the laser treatment modedesired, i.e., vaporization or coagulation. The adjustment to the powerof the laser energy 110 may be performed in accordance with any suitabletechnique, such as adjusting a duty cycle of the laser energy, adjustinga modulation of the laser energy, adjusting the intensity of the inputlight to the laser gain medium of the laser resonator of the lasersource 102, or other technique. Additional adjustments that can be madeinclude, and are not limited to, laser pulse widths, repetition rate,and/or wavelength

FIG. 9 is a flowchart illustrating a method of operating a surgicallaser system 100 in accordance with embodiments of the presentinvention. In general, the method involves using the surgical lasersystem 100 in accordance with one or more of the embodiments describedherein, to perform a laser treatment at a treatment site 121 of apatient. Each of the steps may be performed using the controller 108 inresponse to the execution of program instructions stored in the memory132 or other location, for example.

At 200 of the method, laser energy 110 is generated using a laser source102. At 202, the laser energy 110 is discharged through a fiber 104 tothe treatment site 121. At 204, electromagnetic energy feedback 114 isdelivered to a photodetector 106. At 206, an output signal 112 generatedby the photodetector 106 in response to the electromagnetic energyfeedback 114 is analyzed. At 208, an image 140 is displayed on a display107 based on the output signal 112 using the controller 108.Alternatively, at 208, the laser energy 110 generated by the lasersource 102 can be automatically adjusted by the controller 108 based onthe output signal 112 in order to maintain the desired laser treatmentconditions parameters, i.e., vaporization, coagulation, temperature atthe treatment site/target object, etc. Each of the method steps recitedabove may be performed using one or more of the embodiments of thesurgical laser system 100 disclosed and described above.

In some embodiments of step 206, the output signal 112 from thephotodetector 106 is analyzed in real-time using the controller 108. Insome embodiments, the time-based output signal 112 is used to determinetemperature information in the form of an approximate temperature at thetreatment site 121. This may be accomplished by comparing an intensityof the electromagnetic energy feedback 114 to a look-up table, stored inthe memory 132 or other location, that maps the intensity to acorresponding approximate temperature.

In some embodiments of step 206, the output signal 112 is used todetermine operating mode information in the form of an operating mode ofthe system 100 or a laser treatment being performed at the treatmentsire 121. In some embodiments, the controller 108 compares anapproximate temperature or intensity indicated by the output signal 112to a look-up table, stored in the memory 132 or other location, thatcorrelates the approximate temperature or intensity to a correspondingoperating mode or laser treatment.

In some embodiments, the controller 108 or a suitable frequency analyzeris configured to perform a frequency analysis of the output signal 112to produce a frequency-based output signal 112. In some embodiments, thefrequency-based output, signal 112 is used by the controller 108 todetermine an operating mode of the system 100 or a laser treatment beingperformed at the treatment site 121, as described above.

In some embodiments of step 208, the image 140 produced by thecontroller 108 on the display 107 includes temperature informationand/or operating mode information. In some embodiments, the temperatureinformation indicates an approximate temperature at the treatment site121 based on the output signal 112. In some embodiments, the temperatureinformation includes an alphanumeric and/or graphical representation ofthe approximate temperature indicated by the output signal 112.

In some embodiments, the operating mode information presented in theimage 140 indicates a mode of operation of the system 100, and/or lasertreatment being performed at the treatment site 121. In someembodiments, the operating mode information is representedalphanumerically and/or graphically in the image 140.

Although the present invention has been described with reference topreferred embodiments, workers skilled in the art will recognize thatchanges may be made in form and detail without departing from the spiritand scope of the invention.

What is claimed is:
 1. A surgical laser system comprising: a lasersource configured to generate laser energy; a laser fiber opticallycoupled to the laser source and configured to discharge the laser energyand collect electromagnetic energy feedback from a treatment site; aphotodetector configured to generate an output signal in response to theelectromagnetic energy collected from the treatment site; a display; anda controller configured to produce an image or indication about at leastone condition at the treatment site on the display based on the outputsignal.
 2. The surgical laser system of claim 1, wherein the outputsignal corresponds to a condition at the treatment site.
 3. The surgicallaser system of claim 2, wherein the condition at the treatment site isselected from the group consisting of temperature and treatment mode. 4.The surgical laser system of claim 3, wherein the treatment mode isselected from the group consisting of vaporization and coagulation. 5.The surgical laser system of claim 1, wherein the image includestemperature information, which is based on the output signal, thetemperature information indicating, an approximate temperature at thetreatment site where the laser energy is discharged by the laser fiber,or an average approximate temperature at the treatment site over aperiod of time.
 6. The surgical laser system of claim 5, wherein theimage includes a graphical display of the temperature information or analphanumeric display of the temperature information.
 7. The surgicallaser system of claim 1, wherein the image includes treatment modeinformation based on the output signal the treatment mode informationindicating a laser treatment being performed a treatment site where thelaser energy is discharged by the laser fiber.
 8. The surgical lasersystem of claim 7, wherein the image includes treatment mode boundariesindicating upper and lower operating parameters of at least onetreatment mode.
 9. The surgical laser of claim 1, wherein the controlleris configured to control the laser energy discharged through the laserfiber responsive to the output signal.
 10. The surgical laser system ofclaim 1, further comprising an input device, wherein tire controller isconfigured to control the laser energy discharged through the laserfiber responsive to a user input received through the input device. 11.The surgical laser system of claim 1, wherein the controller isconfigured to convert the output signal from a time-based signal to afrequency-based signal.
 12. The surgical laser system of claim 11,wherein treatment modes are identified using the frequency-based signal.13. A method of operating a surgical laser system comprising the stepsof: generating laser energy using a laser source; discharging the laserenergy through a laser fiber to a treatment site; deliveringelectromagnetic energy feedback from the treatment site produced inresponse to discharging the laser energy to the treatment site to aphotodetector; generating a photodetector output signal; analyzing thephotodetector output signal using a controller; and displaying treatmentsite information on a display based on the photodetector output signalanalyzed by the controller.
 14. The method of claim 13, whereindisplaying the treatment site information includes displayingtemperature information based on the output signal, the temperatureinformation indicative of a temperature at the treatment site.
 15. Themethod of claim 13, wherein displaying the treatment site informationincludes displaying a treatment mode of the surgical laser system.
 16. Amethod of operating a surgical laser system comprising the steps of:generating laser energy using a laser source; discharging the laserenergy through a laser fiber to a treatment site; analyzingelectromagnetic energy feedback from the treatment site produced inresponse to discharging the laser energy to the treatment site; andautomatically adjusting the laser energy based on the analysis of theelectromagnetic energy feedback.
 17. The method of claim 16, wherein theelectromagnetic energy feedback is delivered to a photodetector forgenerating a photodetector output signal.
 18. The method of claim 17,wherein a controller is used to analyze the photodetector output signal.19. The method of claim 18, wherein the controller automatically adjustthe laser energy in response to the photodetector output analysis. 20.The method of claim 19, wherein adjusting the laser energy is selectedfrom the group consisting of adjusting the laser power, adjusting a dutycycle of the laser energy, adjusting a modulation of the laser energy,adjusting an intensity an input light to a laser gain medium of a laserresonator of the laser source, adjusting laser pulse widths, adjustingrepetition rate and adjusting a wavelength.